1. Field of the Invention
The present invention relates to a display device and, more particularly, to a technique effectively applied to a touch panel-integrated display device in which a touch panel function is incorporated in a liquid crystal display panel.
2. Description of the Related Art
A display device including a device referred to as a touch sensor or a touch panel for applying touch operation (contact and pressing operation, hereinafter simply referred to as touch) to a display screen using a finger of a user, a pen, or the like to input information is used for mobile electronic devices such as a PDA and a portable terminal, various household electric appliances, an automated teller machine, and the like. As such a touch panel, a resistance film type for detecting a resistance value change in a touched portion, a capacitance type for detecting a capacitance change, an optical sensor type for detecting alight amount change, and the like are known.
In the touch panel of the capacitance type, scanning electrodes (Y electrodes) for driving signal application arranged in a two-dimensional matrix shape lengthwise and crosswise and detection electrodes (X electrodes) for signal detection orthogonal to the scanning electrodes are provided. An input processing unit detects capacitances of the electrodes. When a conductor such as a finger comes into contact with the surface of the touch panel, the capacitances of the electrodes increase. Therefore, the input processing unit detects the increase in the capacitances and calculates an input coordinate on the basis of signals of capacitance changes detected by the electrodes.